1. Field of the Invention
The present invention relates to a stamp apparatus. More particularly, the invention relates to a stamp apparatus for preventing a used stencil plate from being reused in plate making.
2. Description of Related Art
FIG. 14 shows a conventional press type mimeograph machine that uses thermal stencil paper perforated by infrared radiation or by heat application from a thermal head. Thermal stencil paper 300 used on this machine is made of a thermoplastic film glued on a porous base material, the latter being surrounded by a frame 302. The frame 302 and an ink-impervious cover sheet 304 combine to form an engraved portion 314 to which ink is applied. The thermal stencil paper 300, frame 302, cover sheet 304 and engraved portion 314 constitute a thermal stencil plate 306.
The mimeograph machine comprises a press member 308, a cradle 310 opposed to the press member 308, and a retaining member 312 for retaining the thermal stencil plate 306. The retaining member 312 is located around the periphery of that part of the press member 308 that faces the cradle 310.
For the above mimeograph machine to operate, the thermal stencil paper 300 of the stencil plate 306 is first perforated by the thermal head of a plate-making mechanism of the machine. Ink is applied to the engraved portion 314 within the frame 302 of the thermal stencil plate 306. Then, the cover sheet 304 is placed onto the engraved portion 314 with the frame 302 held therebetween, and the thermal stencil plate 306 is retained by the retaining member 312 against the press member 308. The press member 308 is pressed onto the cradle 310 with printing paper 316 placed therebetween. The pressing action forces the ink through the perforations of the thermal stencil paper 300 onto the printing paper 316 for printing thereon.
One disadvantage of the above prior art machine is that the user is required to apply ink manually to the stencil plate. In doing so, the user tends to get dirty hands or smeared clothes. In addition, irregular application of ink by an inexperienced user can result in uneven densities in printing.
Another disadvantage of the prior art machine is that the user can inadvertently set thermal stencil paper 300 already used onto the plate-making mechanism of the machine for making another plate. This can lead to many problems including the plate not being perforated appropriately, the ink residue on the thermal stencil paper 300 sticking to heat-generating parts on the thermal head, and/or ink being trapped in the plate-making mechanism.